If the wreckage is not retrieved, investigators will have very little to go by on to get to the reason behind the disappearance.

NEW DELHI: Even as the window is closing on finding the coast guard Dornier aircraft that went missing with a crew of three off Chennai last week, the disappearance of a brand new plane coming back from a routine patrolling mission has baffled experts and insiders with a growing fear that the mystery may never be resolved.

One of the largest ever joint sea search efforts mounted by India is currently underway in the Bay of Bengal with several ships, a submarine and specialized search vessels straining to catch a fading emergency transmission believed to be coming from the bottom of the sea.

While searchers are hopeful of locating the wreckage with sea bed mapping equipment that has been requested from a research vessel of the national institute of ocean technology, retrieving critical equipment like data recorders would be extremely difficult as the aircraft - designated CG 791 - is believed to be lost at a depth of over 700 meters.

Sources say that while a deep sea remotely operated vessel has been requested from Reliance Industries - the only one of its kind available that is used by the company for its offshore facilities - the window is closing as the aircraft has been lost for over a week and its transmission beacon is now sending only a very feeble signal that is being tracked by Kilo class submarine INS Sindhudhwaj.

If the wreckage is not retrieved, investigators will have very little to go by on to get to the reason behind the disappearance. The circumstances in which the aircraft was lost has left all baffled - CG 791 had been inducted into service in 2014 and was in impeccable working condition. It was flying in perfect weather, at a lofty altitude of 9000 feet when it suddenly disappeared from the radar without any warning.

Dornier aircraft, by their very design are sturdy and capable of a controlled ditching into the sea even after losing both engines. Officials said that even if the aircraft had experienced a technical fault, the crew would have had adequate time to send out an alert or emergency call to military air traffic controllers.

However, just 23 minutes after the crew gave an 'Ops Normal' call to the Trichy station that was tracking it, CG 791 disappeared from the radar, on a steady flight path to Chennai. "The last contact with the aircraft was about 2100 hours and the Trichy radar tracked the aircraft till 2123 at position 95 nautical miles south of Chennai," a Coast Guard official said.

The missing aircraft was being flown by a very experienced crew of three with hundreds of hours of flying experience between them. "There was no distress call or a SoS to anyone. No emergency transmission came even after it disappeared from the radar," an official confirmed.

This has added to the mystery as emergency beacons of naval aircraft are automatically activated it hits water or suffers physical damage. It took the searching party almost five days to pick up any signal of the missing aircraft after naval vessels got a fading emergency transmission from deep underwater at the location CG 791 vanished from radar.

Another unusual fact is the absence of any debris in the area where it vanished. "Usually, a downed aircraft would have a wide spread of debris that can be spotted from the air or from sea. However, not a single sign of the aircraft has been found, barring a patch of oil that could be from CG 791," the official added.

A sturdy workhorse, the Dornier has an impeccable safety record with only two being lost in over two decades of service. A crash earlier this year of a Navy Dornier is feared to have occurred due to a human error as the aircraft was on a low level flying training mission.

While efforts will continue to hunt for CG 791, there are growing fears that the missing aircraft may have taken its secrets to the seabed where it is now believed to be lying. The families of the three crew members have been waiting for any news of the aircraft and while top officials including Defence Minister Manohar Parrikar are in touch with them, the is little that can console them till the mystery is solved.

Parrikar takes stock of Navy's operational readiness

9 Apr, 2015

Economictimes.com & PTI

Defence Minister Manohar Parrikar recently undocked a Indian Navy's first scorpene class stealth submarine, visited INS Viraat and was apprised about the operational responsibilities of the Western Naval Command.

We take a look at some choicest images of his visit to Mumbai:

INS Viraat

9 Apr, 2015

Parrikar visited INS Viraat, where he was briefed about the ship and development plans of Naval Dockyard (Mumbai).

Image by Ministry of Defence

INS Sindhukesari

9 Apr, 2015

Parrikar also visited INS Sindhukesari (EKM Submarine) in the harbour for a first-hand experience of an operational submarine. He was briefed on the operating environment in submarines.

Image by Ministry of Defence

Undocked Kalvari

9 Apr, 2015

Parrikar undocked Kalvari, the first of Indian Navy's Scorpene class stealth submarines being built under Project 75.

Project 75, which has already seen a delay of almost 40 months, has now been brought on track and the delivery schedule for the successive submarines has been reduced.

Image by DPR, Ministry of Defence

m2.jpg

9 Apr, 2015

According to the Navy, the Scorpene submarines would pack a potent punch. They would be equipped with anti-ship missiles and long range guided torpedoes along with modern sensor suite.